0.3.4 AS5600

libraries/AS5600/AS5600.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: AS56000.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.3
+// VERSION: 0.3.4
 // PURPOSE: Arduino library for AS5600 magnetic rotation meter
 //    DATE: 2022-05-28
 //     URL: https://github.com/RobTillaart/AS5600
@@ -311,27 +311,12 @@ uint8_t AS5600::getWatchDog()
 uint16_t AS5600::rawAngle()
 {
   int16_t value = readReg2(AS5600_RAW_ANGLE) & 0x0FFF;
-
-  //  whole rotation CW?
-  if ((_lastPosition > 2500) && ( value < 1500))
-  {
-    _position = _position + 4096 - _lastPosition + value;
-  }
-  //  whole rotation CCW?
-  else if ((value > 2500) && ( _lastPosition < 1500))
-  {
-    _position = _position - 4096 - _lastPosition + value;
-  }
-  else _position = _position - _lastPosition + value;
-  _lastPosition = value;
-
   if (_offset > 0) value = (value + _offset) & 0x0FFF;
 
   if ((_directionPin == 255) && (_direction == AS5600_COUNTERCLOCK_WISE))
   {
     value = (4096 - value) & 0x0FFF;
   }
-
   return value;
 }
 
@@ -466,8 +451,24 @@ float AS5600::getAngularSpeed(uint8_t mode)
 //
 //  POSITION cumulative
 //
+
 int32_t AS5600::getCumulativePosition()
 {
+  int16_t value = readReg2(AS5600_RAW_ANGLE) & 0x0FFF;
+
+  //  whole rotation CW?
+  if ((_lastPosition > 2048) && ( value < (_lastPosition - 2048)))  //  less than half a circle
+  {
+    _position = _position + 4096 - _lastPosition + value;
+  }
+  //  whole rotation CCW?
+  else if ((value > 2048) && ( _lastPosition < (value - 2048)))  //  less than half a circle
+  {
+    _position = _position - 4096 - _lastPosition + value;
+  }
+  else _position = _position - _lastPosition + value;
+  _lastPosition = value;
+
   return _position;
 }
 

libraries/AS5600/AS5600.h

@@ -2,7 +2,7 @@
 //
 //    FILE: AS5600.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.3
+// VERSION: 0.3.4
 // PURPOSE: Arduino library for AS5600 magnetic rotation meter
 //    DATE: 2022-05-28
 //     URL: https://github.com/RobTillaart/AS5600
@@ -12,7 +12,7 @@
 #include "Wire.h"
 
 
-#define AS5600_LIB_VERSION              (F("0.3.3"))
+#define AS5600_LIB_VERSION              (F("0.3.4"))
 
 //  default addresses
 const uint8_t AS5600_DEFAULT_ADDRESS    = 0x36;
@@ -210,9 +210,12 @@ public:
   float    getAngularSpeed(uint8_t mode = AS5600_MODE_DEGREES);
 
   //  EXPERIMENTAL CUMULATIVE POSITION
+  //  reads sensor and updates cumulative position
   int32_t  getCumulativePosition();
+  //  converts last position to whole revolutions.
   int32_t  getRevolutions();
-  int32_t  resetPosition();    //  resets counter returns last value.
+  //  resets position, returns last position.
+  int32_t  resetPosition();
 
 
 protected:

libraries/AS5600/CHANGELOG.md

@@ -5,6 +5,13 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.3.4] - 2022-12-22
+- fix #26 edges problem of the experimental cumulative position (CP).
+- decoupled CP from **rawAngle()**
+  - now one needs to call **getCumulativePosition()** to update the CP.
+- updated the readme.md section about CP.
+
+
 ## [0.3.3] - 2022-12-19
 - add experimental continuous position.
   - add **getCumulativePosition()**
@@ -18,7 +25,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - add AS5600L_DEFAULT_ADDRESS
 - update readme.md
 
-
 ## [0.3.2] - 2022-10-16
 - add CHANGELOG.md
 - update readme.md

libraries/AS5600/README.md

@@ -301,21 +301,39 @@ with a short interval. The only limitation then is that both measurements
 should be within 180° = half a rotation. 
 
 
-### Cumulative position
+### Cumulative position (experimental)
+
+Since 0.3.3 an experimental cumulative position can be requested from the library.
+The sensor does not provide interrupts to indicate a movement or revolution
+Therefore one has to poll the sensor at a frequency at least 3 times per revolution with **getCumulativePosition()**
+
+The cumulative position consists of 3 parts
+
+|  bit    |  meaning      |  notes  |
+|:-------:|:--------------|:--------|
+|    31   |  sign         |  typical + == CW, - == CCW
+|  30-12  |  revolutions  |
+|  11-00  |  raw angle    |  call getCumulativePosition() 
+
+
+Functions are:
+
+- **int32_t getCumulativePosition()** reads sensor and updates cumulative position.
+- **int32_t getRevolutions()** converts last position to whole revolutions.
+Convenience function.
+- **int32_t resetPosition()** resets **revolutions**, returns last position. 
+The cumulative position does not reset to 0 but to the last known raw angle.
+This way the cumulative position always indicate the (absolute) angle too.
+
+As this code is experimental, names might change in the future.
+As the function are mostly about counting revolutions the current thoughts for new names are:
 
 ```cpp
-  //  EXPERIMENTAL CUMULATIVE POSITION
-  int32_t  getCumulativePosition();
-  int32_t  getRevolutions();
-  int32_t  resetPosition();    //  resets position returns last value.
+int32_t updateRevolutions()  replaces getCumulativePosition()
+int32_t getRevolutions()
+int32_t resetRevolutions()   replaces resetPosition()
 ```
 
-to elaborate
-
-- call rawAngle() often enough == at least 4x per rotation
-- example
-- only the revolutions are reset
-
 
 ### Status registers
 

libraries/AS5600/examples/AS5600_position/AS5600_position.ino

@@ -39,9 +39,12 @@ void setup()
 void loop()
 {
   static uint32_t lastTime = 0;
-  //  Serial.print("\ta = ");
-  //  Serial.print(as5600.readAngle());
-  as5600.rawAngle();
+
+  //  set initial position
+  as5600.getCumulativePosition();
+
+  //  update every 100 ms
+  //  should be enough up to ~200 RPM
   if (millis() - lastTime >= 100)
   {
     lastTime = millis();
@@ -49,7 +52,12 @@ void loop()
     Serial.print("\t");
     Serial.println(as5600.getRevolutions());
   }
-  if (as5600.getRevolutions() >= 10) as5600.resetPosition();
+
+  //  just to show how reset can be used
+  if (as5600.getRevolutions() >= 10)
+  {
+    as5600.resetPosition();
+  }
 }
 
 

libraries/AS5600/library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/AS5600.git"
   },
-  "version": "0.3.3",
+  "version": "0.3.4",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

libraries/AS5600/library.properties

@@ -1,5 +1,5 @@
 name=AS5600
-version=0.3.3
+version=0.3.4
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Arduino library for AS5600 and AS5600L magnetic rotation meter.